error: use golang.org/x/xerror

Author: zchee

error.go

@@ -6,29 +6,40 @@ package jsonrpc2
 
 import (
 	"fmt"
+
+	"golang.org/x/xerrors"
 )
 
+// Code represents a error's category.
 type Code int64
 
 const (
-	CodeParseError           Code = -32700
-	CodeInvalidRequest       Code = -32600
-	CodeMethodNotFound       Code = -32601
-	CodeInvalidParams        Code = -32602
-	CodeInternalError        Code = -32603
-	CodeServerErrorStart     Code = -32099
-	CodeServerErrorEnd       Code = -32000
-	CodeServerNotInitialized Code = -32002
-	CodeUnknownErrorCode     Code = -32001
+	// CodeParseError is the invalid JSON was received by the server. An error occurred on the server while parsing the JSON text.
+	CodeParseError Code = -32700
+	// CodeInvalidRequest is the JSON sent is not a valid Request object.
+	CodeInvalidRequest Code = -32600
+	// CodeMethodNotFound is the method does not exist / is not available.
+	CodeMethodNotFound Code = -32601
+	// CodeInvalidParams is the invalid method parameter(s).
+	CodeInvalidParams Code = -32602
+	// CodeInternalError is the internal JSON-RPC error.
+	CodeInternalError Code = -32603
 
-	// Defined by the protocol.
+	// CodeServerNotInitialized is the error of server not initialized.
+	CodeServerNotInitialized Code = -32002
+	// CodeUnknownError should be used for all non coded errors.
+	CodeUnknownError Code = -32001
+	// CodeRequestCancelled is the cancellation error.
 	CodeRequestCancelled Code = -32800
-	CodeContentModified  Code = -32801
+	// CodeContentModified is the state change that invalidates the result of a request in execution.
+	CodeContentModified Code = -32801
+
+	codeServerErrorStart Code = -32099
+	codeServerErrorEnd   Code = -32000
 )
 
-// Error
+// Error represents a jsonrpc2 error.
 type Error struct {
-
 	// Code a number indicating the error type that occurred.
 	Code Code `json:"code"`
 
@@ -38,20 +49,51 @@ type Error struct {
 
 	// Message a string providing a short description of the error.
 	Message string `json:"message"`
+
+	frame xerrors.Frame
+	err   error
 }
 
+// Error implements error.
 func (e *Error) Error() string {
 	if e == nil {
 		return ""
 	}
 	return e.Message
 }
 
+// Format implements fmt.Formatter.
+func (e *Error) Format(s fmt.State, c rune) {
+	xerrors.FormatError(e, s, c)
+}
+
+// FormatError implements xerrors.Formatter.
+func (e *Error) FormatError(p xerrors.Printer) (next error) {
+	if e.Message == "" {
+		p.Printf("code=%v", e.Code)
+	} else {
+		p.Printf("%s (code=%v)", e.Message, e.Code)
+	}
+	e.frame.Format(p)
+
+	return e.err
+}
+
+// Unwrap implements xerrors.Wrapper.
+//
+// The returns the error underlying the receiver, which may be nil.
+func (e *Error) Unwrap() error {
+	return e.err
+}
+
 // Errorf builds a Error struct for the suppied message and code.
-// If args is not empty, message and args will be passed to Sprintf.
-func Errorf(code Code, format string, args ...interface{}) *Error {
-	return &Error{
-		Code:    code,
+func Errorf(c Code, format string, args ...interface{}) *Error {
+	e := &Error{
+		Code:    c,
 		Message: fmt.Sprintf(format, args...),
+		frame:   xerrors.Caller(0),
 	}
+	e.err = xerrors.New(e.Message)
+
+	return e
 }